drivers/gpu/drm/i915/intel_dp.c: pps_{lock,unlock}: cannot annotate due to aliasing

[bulwahn]

drivers/gpu/drm/i915/intel_dp.c:620:1: warning: mutex 'dev_priv->pps_mutex' is still held at the end of function [-Wthread-safety-analysis]
}
^
drivers/gpu/drm/i915/intel_dp.c:617:2: note: mutex acquired here
        mutex_lock(&dev_priv->pps_mutex);
        ^
drivers/gpu/drm/i915/intel_dp.c:627:2: warning: releasing mutex 'dev_priv->pps_mutex' that was not held [-Wthread-safety-analysis]
        mutex_unlock(&dev_priv->pps_mutex);
        ^